Primary pulmonary histiocytosis X.

During the past 40 years, three previously unrecognized disorders of the reticuloendothelial system have been described : Letterer-Siwe’s disease,’ Hand-Sch#{252}ller-Christian’s disease,24 and eosinophilic granuloma.5’6 Due largely to the influence of Lichtenstein,7 the opinion now prevails that these three disorders are fundamentally related. They differ from one another mainly in terms of patient’s age at onset and rapidity of progression. The microscopic pathologic feature characteristic of each of these conditions is the infiltration of tissue by large numbers of histiocytes. The etiology in each instance is unknown. For those reasons Lichtenstein proposed the term “histiocytosis X” to encompass all three disorders.7 It has been known for some time that histiocytosis X may have its origin in an organ or organic system other than the lung, and that it may involve the lungs later during the course of dissemination.8 More recently a number of cases have been reported in which the disease apparently originated in the lung.99 Various terms have been used to designate this form of histiocytosis X, including eosinophilic granuloma of the lung,9’2”62#{176}primary pulmonary eosinophilic granuloma,’4 and pulmonary histiocytosis X.’5 The term “primary pulmonary histiocytosis X” is perhaps more appropriate, since it refers to both the site of origin and the basic pathology of the disease process. In a few of the cases of primary pulmonary histiocytosis X reported in the literature, diabetes insipidus occurred as a complicating condition.”3 However, no case has yet been reported in which histiocytosis X involved the lungs primarily and then later became widely disseminated with evidence of osseous and other visceral involvement. In an effort to learn more of the natural history and influence of various forms of treatment on this disease, the experience with primary pulmonary histiocytosis X at the Mayo Clinic was reviewed. The present paper summarizes this experience and makes certain comparisons with the experiences of others already recorded in the literature. In addition, future avenues of study of patients with primary pulmonary histiocytosis X are suggested.